Multiple Technologies Combined to Analyze the Changes of Odor and Taste in Daokou Braised Chicken during Processing

This study analyzed the changes of odor and taste in Daokou braised chicken during processing by GC-MS, GC-IMS, e-nose and e-tongue. The 75 and 55 volatile compounds identified in Daokou braised chicken by GC-MS and GC-IMS, respectively, included hydrocarbons, aldehydes, alcohols, terpenes, ketones, heterocyclics, esters, acids and phenols; among them, aldehydes, alcohols and ketones were the most abundant. The number and proportion of volatile compounds in Daokou braised chicken changed significantly (p < 0.05) in the process. The proportion of volatile compounds with animal fatty odor, such as aldehydes and alcohols, decreased, while that of esters, ketones and terpenes from spices with fruity fragrance increased, especially in the braising stage. An e-nose showed that the odor intensities of sulfur-containing and nitrogen oxide compounds were higher (p < 0.05) after the braising stage, but weakened after 2 h braising. An e-tongue showed that saltiness and richness increased significantly (p < 0.05) after braising. The results of these four techniques showed that braising promoted the release of flavor compounds, and was beneficial to salt penetration and umami release. However, long braising could lead to weakened flavor intensity and the introduction of bitterness and astringency. This study also found that GC-IMS and e-nose were more sensitive to trace compounds such as sulfur-containing and nitrogen oxide compounds, esters, acids and phenolics in Daokou braised chicken than GC-MS. The use of multiple technologies could provide more comprehensive flavor profiles for Daokou braised chicken during processing. This study provides insights into the control of flavor of Daokou braised chicken, and may be of practical relevance for the poultry industry.